Induction of DNA polymerase in mixed lymphocyte cultures

Histocompatibility is frequently determined by serological typing of lymphocytes for HL-A alloantigens. This method is restricted by the availability of specific antisera and may be hampered by undetected antigens. There is, however, no restriction on the choice of antigenic determinants in mixed leucocyte culture reactions. When lymphocytes from the peripheral blood of two individuals are mixed and cultured together, the extent of stimulation seems to be a function of disparities in histocompatibility. "One way stimulation" can also be studied by preventing replication of either set of lymphocytes by prior treatment with mitomycin C (ref. 5) or by X-irradiation. The morphological observation of blastogenesis and measurements of the uptake of H-thymidine into cellular DNA have been used to monitor stimulation, but they have deficiencies